Yuzo Iano

A fast and efficient hybrid fractal-wavelet image coder

The excellent visual quality and compression rate of fractal image coding have limited applications due to exhaustive inherent encoding time. This paper presents a new fast and efficient image coder that applies the speed of the wavelet transform to the image quality of the fractal compression. Fast fractal encoding using Fishers domain classification is applied to the lowpass subband of wavelet transformed image and a modified set partitioning in hierarchical trees (SPIHT) coding, on the remaining coefficients. Furthermore, image details and wavelet progressive transmission characteristics are maintained, no blocking effects from fractal techniques are introduced, and the encoding fidelity problem common in fractal-wavelet hybrid coders is solved. The proposed scheme promotes an average of 94% reduction in encoding-decoding time comparing to the pure accelerated Fractal coding results. The simulations also compare the results to the SPIHT wavelet coding. In both cases, the new scheme improves the subjective quality of pictures for high-medium-low bitrates.

Re-Multiplexing ISDB-T BTS Into DVB TS for SFN

The Single Frequency Network (SFN) allows a single TV channel to cover a great area in the same frequency, increasing the spectrum efficiency and signal quality. In this case, all the programs are re-multiplexed into a Transport Stream (TS) and distributed to the re-transmitter stations. The Integrated Digital Services Broadcasting-Terrestrial (ISDB-T) has been projected to operate in SFN, and uses a TS-adapted version called Broadcast Transport Stream (BTS). The BTS has a constant bit rate and packet size of 204 bytes. Owing to these characteristics, most network adapters are non compliant with this signal type. This article proposes a new re-multiplexer algorithm of the BTS signal that allows the encapsulation of the BTS into the Digital Video Broadcasting Transport Stream (DVB TS) and vice versa. This technique makes the BTS distribution possible through satellite, allowing the large SFN construction and accomplishing lesser bit rate than the original BTS.

Reliability and validity of digital assessment of perifoveal capillary network measurement using high-resolution imaging

Background Assessment of the perifoveal capillary network (PCN) might indicate macular function and could reflect the systemic microcirculation. The quantification and reliability of this measurement is currently unknown. The aim of this study was to validate quantification of the PCN by a non-invasive technique from high-resolution retinal images. Methods Ten healthy volunteers were included in this validation study. At least 320 high-resolution retinal images were used for assessment of inter- and intra-observer reliability. Non-invasive capillary perfusion mapping was performed using a retinal function imager. After the images were enhanced and segmented, the reproducibility was verified by comparing the values of two independent examiners and of a single examiner at two different time points. Results The inter-observer concordance coefficients were highly significant for PCN (intraclass correlation coefficient (ICC)=0.901, 95% CI 0.655 to 0.975, p<0.001) and normalised PCN (ICC=0.727, 95% CI 0.262 to 0.923, p=0.004). The intra-observer measurements at two different time points were also highly concordant for PCN (ICC=0.879, 95% CI 0.598 to 0.968, p<0.001) and for normalised PCN (ICC=0.960, 95% CI 0.851 to 0.990, p<0.001). Conclusions The reliability of PCN measurement is reproducible and could be used as a new tool to quantify the capillary perfusion network of the macular area.

Implementation of a fixed-point 2D Gaussian Filter for Image Processing based on FPGA

One of the very useful techniques in Image Processing is the 2D Gaussian Filter, especially when smoothing images. However, the implementation of a 2D Gaussian Filter requires heavy computational resources, and when it comes down to real-time applications, efficiency in the implementation is vital. Floating-point math represents an obstacle for this, as its implementation requires a large amount of computational power in order to achieve real-time image processing. On the other hand, a fixed-point approach is much more suitable; implementation of a 2D Gaussian Filter in FPGA using fixed-point arithmetic provides efficiency in the processing and reduction in computational costs. The purpose of this study is to present the FPGA resource usage for different sizes of Gaussian Kernel; to provide a comparison between fixed-point and floating point implementations; and to define the amount of bits are necessary to use in order to have a Root Mean Square Error (RMSE) below 5%.

How to architect an IPTV system

Todays Internet Protocol Television (IPTV) is being offered and taking off, driving radical changes in the way telecom networks are designed. Future consumers will look for unique, personalized services through multiple devices, including the television. On demand content, Interactive TV, Video and voice communications, photo, music, and home video sharing, and online gaming, all delivered seamlessly, are a few examples of the services that consumers could receive. This requires innovative changes in the entire end-to- end service delivery architect, quality of service and customer management, reliability and security.

Matching Interactive TV and Hypervideo

The paper reports an approach to develop an interactive TV system based on the concept of hypervideo. The great innovation the concept of hypervideo proposed in this paper brings is the possibility to associate different complementary information about the objects shown in scene. The association between those complementary information and video is made by embedding hyperlinks (references) into a digital video being transmitted, allowing the user to access such information by clicking in an area of the image being watched. This is an innovative approach for interactive television in the sense that it admits the association of video and context sensitive information. A concept proof prototype, developed to illustrate the ideas proposed, is presented in this paper.

SCORM-MPEG: An ontology of interoperable metadata for multimedia and e-Learning

The convergence of digital media offers an integration of ICT focused on telecommunications and multimedia domain (under responsibility of the Moving Picture Experts Group, ISO/IEC JTC1 SC29) and the ICTE (the ICT for Education), managed by the ISO/IEC JTC1 SC36, highlighting the MPEG standards, employees as content and metadata to the multimedia Digital TV and the technologies applied to e-Learning. Regarding this, there is the problem of developing an interoperable matching for normative bases, achieving an innovative proposal in the convergence between digital telecommunications and applications for e-Learning, also essentially multimedia. To reach this purpose it is proposed to create a standard ontology of interoperable metadata for web, digital TV and extensions for mobile devices based on the integration between MPEG-21 and SCORM metadata standards. The methodology used consists on building an ontology MPEG-21 SCORM which can be achieved on making a correspondence through the XPath language, managed by the W3C. The employ of the XPath language is desirable for matching and mapping both metadata schema patterns - integrating MPEG-21 (mostly Digital Item Declaration Language) and SCORM metadata schema. The practical purpose is the creation and storage of objects for use in digital telecommunications as Digital Television, in an interoperable way with the e-Learning industry, here as description metadata for all sorts of media and hypermedia to create learning objects.

ISDB-Tb field trials and coverage measurements with gap-filler in suburban environments

The expansion of digital television in South America and Africa demand new cheaper solutions for the coverage problem. The use of gap-fillers and SFN are very important instruments to design broadcasting television. Many countries start trials and tests according their particularities. The solutions found are been related in papers and make a valuable acknowledge for future projects related. Comparison between field application and coverage prediction software optimize the results of broadcasting network. This paper presents the results of a field measurement with Gap-Filler in suburban environment. This paper presents the results of a field measurement and a description of implantation of a Gap-Filler in suburban environment‥

Distributed Video Coding Using Turbo Codes and Second Generation Wavelets

Distributed video coding is a new paradigm for video compression in opposition over the existing video coding standards like MPEG-x and H.26x families. These codecs make use of motion estimation algorithms, the main part of the compression process of the video signal. Hence, the compression process demands a high computational cost and high performance of the encoder. The present work proposes a video compression scheme based on the lossy distributed source coding theory. The proposed compressor encodes the odd frames and the even frames separately using turbo codes and the discrete wavelet transform. The decoding process is performed in a iterative manner and explores the statistical dependency of the video frames of the original sequence. This approach gives a great encoding runtime reduction and allows the implementation at devices with limited computation power and memory. Simulation results show the good performance of the proposed codec in comparison with the state of the art video compression standard H.264/AVC.

Expansion Planning of the Digital TV Broadcasting Service in Brazil using SFN

This work aims to discuss briefly the relevant technical aspects for introduction and expansion of Digital TV retransmission services based on OFDM Multiplexing. The initial channel allocation, proposed for introduction of Digital TV in Brazil, will carry the spectral overload problems of the current analogical systems.The use of single frequency networks (SFN) appears as an efficient solution for channel allocation.